Electric fence indicator



CL; A) O za- Dec. 15, 1942 c. PFANSTIEHL 2,304,954

ELECTRIC FENCE INDICATOR Filed Oct. 23, 1940 Patented Dec. 15, 1942 VUNITED STATES PATENT, OFFICE 2,304,954 I ELECTRIC FENCE mmca'roa CarlPfanstiehl, Highland Park, 111.; Caryl cm- Pfanstiehl execntrix of CarlPfanstielil, deceased, assignoito Babson Bros. 00.,

Chicago,

111., a corporation of Illinois Application October 23, 1940, Serial No.362,451

3Claims.

This invention relates to an electric fence indicator, and moreparticularly to means for determining the true effectiveness of anelectric fence in its function of stopping and holding cattie or otheranimals.

One feature of this invention is that it provides improved means forindicating the true effectiveness of a normally open circuit electricfence; another feature of this invention is that the indication is atrue reflection of the eifectiveness of the fence, despite variouschanges in its conditions; a further feature of this invention is thatthe indicating means is very simple, rugged, and easily manufactured andused; other features and advantages of this invention will be apparentfrom the following specification and the drawing, in which:

Figure 1 is a front elevation of an electric fence controller orenergizing device embodying my invention; Figure 2 is a fragmentaryelevation of the means providing a visual indication of theeffectiveness of the fence; and Figure 3 is a schematic diagram ofapparatus embodying my invention.

This present application is a continuation-inpart of my earlierapplication, Serial No. 243,244 filed November 30, 1938, and entitled"Signal device for an electric fence, which application was a divisionalof my earlier application Serial No. 238,914, filed November 9, 1938,entitled Electric fence," which issued July 15, 1941, as Patent No.2,249,696, and is more particularly directed to a transformer forproviding a plurality of voltages.

Electric fences are intended to stop and hold animals by electricshocks, rather than by their mechanical strength, the'shock used beingstrong enough to cause the animal to avoid the fence but not strongenough to permanently injure the animal or anyone accidentally coming incontact with the fence. In order to insure safety of such fences it hasbeen determined that the maximum current deliverable to the fence shouldnot exceed twenty-five mllliamperes, and current flow should beintermittent, current being supplied to the fence wire not more thanone-tenth second and about once a second. State and other codes haveincorporated these and similar requirements, and electric fences nowsold normally incorporate a circuit interrupter in the primary designedto close the circuit for less than one-tenth second approximately onceeach second; and some means is included to limit the output current totwenty-five miliiamperes.

Inasmuch as an electric fence normally comprises only a single fencewire, and since this fence wire is sometimes strung for a distance ofseveral miles, it is highly desirable to provide an indication at thecontroller or energizing apparatus to indicate whether the fence isoperative. Original indicators employed merely showed whether or not anycurrent was reaching the fence at the desired intervals, as by placing asmall filament lamp in series with the fence; more recent indicatorshave in some cases endeavored to reflect the condition of the fence, sothat the farmer may know whether it is effectlve to hold his cattle.Such fences are generally strung from insulators from fence posts, andtrouble with. poor insulation is frequently encountered: moreover, weedsfrequently grow into contact with the fence wire and provide a partialground of varying degree, this same type of ground being encounteredfrom bushes or leaves of the fence render such a method a poorindication of the true efiectiveness of the fence in stopping animals.Variations in fence length and height from the ground, for example,cause variations in the fence-to-ground capacity. A

'. large capacity, as that-of three or four miles of fence wire, maycause-a considerable charging current to flow into the fence each timethe secondary of the transformer in the controller is energized eventhough the fence is in optimum condition. Moreover, capacities whichhappen to cause resonance conditions with the secondary of thetransformer, or an approach to such conditions, frequently causeabnormal currents to flow in the fence wire even though the phaseconditions are such that there is little or no power loss, and the fenceis in good condition and highly effective. I have found that the bestindication of the true effectiveness of the fence v for its desiredfunction is the voltage existing between the fence wire and ground uponeach energization; and I am here disclosing a simple, rugged andeffective means for indicating the effectiveness of the fence as afunction of suchvoltage.

In the particular embodiment of my invention illustrated herewith acasing l adapted to be hung on the wall of a ham or the like enclosesthe operative parts for energizing the fence from a conventionalcommercial source of current, manually rotatable elements I I and I2being provided for purposes to be hereinafter more fully described. Aglass bull's-eye or similar means l3 enables the condition of a neon orsimilar glow tube to be seen; and the make and break mercury switch IIis also visible from the front of the casing.

Turning now more particularly to the schematic diagram of Figure 3, itwill be seen that the source of conventional current, as 110 volts A.0., is supplied by the two wires l5 and IE to a small motor i1,preferably of synchronous type, and to the primary IQ of a transformer,the circuit through the primary being completed through the mercury makeand break switch it. The mercury switch is mounted to be rocked back andforth by the lever l9, which is oscillated by a crank arm or eccentric20 driven through a gear train by the motor I1. Each time the mercuryswitch is rocked from one side to the other the small drop M of mercurytouches the two contacts in passing and completes the circuit throughthe primary iii of the transformer. This energization of the primary isvery brief, however, being less than one-tenth of a second; and thegearing and rate of rotation of the motor i1 is such that the contact ismade approximately once each second.

The secondary 22 of the transformer is here I shown as having its upperend connected by the lead wire 23 to a fence wire 24 supported by theposts 25. It is understood that this fence wire is normally insulatedfrom ground in approved manner, as by supporting it from the fence postsby porcelain or similar insulators. The bottom end of the secondary 22is connected to ground by the wire 26, so that any voltage developedacross the secondary 22 is applied between the fence wire 24 and ground,and causes a shock to any animal contacting the fence and completing thecircuit to ground.

The transformer is of the step-up type, preferably raising the voltageto somewhere between one thousand and two thousand volts open circuit.In a commercial embodiment of my invention (fully illustrated anddescribed in my above mentioned Patent No. 2,249,696) a tapped secondarytransformer is used providing a plurality of secondary voltages, as morefully explained in one of my above-mentioned applications; but forsimplicity I here show only one voltage condition, which may beconsidered to correspond to the setting of the switch l2. Thetransformer is, of course, of the type which is self-limiting as tomaximum current deliverable, this being accomplished by a central shuntpath provided by the leg 21 of the transformer.

Since the voltage applied to the fence is normally quite high, I employmeans for providing energized by the subsidiary secondary 28. I haveemployed a sufficient number of turns in the subsidiary secondary toprovide 150 volts on open circuit when the entire secondary 22 isproviding 780 volts on open circuit, for example; and have used a 6,000ohm resistor for the fixed resistance 30 and a 15,000 ohm to zerovariable resistance corresponding to the variable resistance- 32. Themanually rotatable indicator ll operates the variable resistance 32, thefull 15,000 ohms being in circuit when the pointer is clear to the leftof its swing and no resistance being in circuit when the pointer isclear to the right of its swing.

In shunt with the variable resistor 32 is a glow lamp 33. While this maybe of any type employing vapor or inert gas and activated at apredetermined voltage, I find conventional neon tubes or glow lamps veryacceptable. The one which has been employed in a commercial embodimentof this invention has a break-down voltage of 46 volts. Such lamps canbe obtained on the market quite cheaply, and their breakdown voltagestays within fairly close limits. It will be readily seen that thevoltage developed across the plates or elements of the glow lamp 33 is afunction of the voltage across the variable resistance 32, which is inturn a function both of its setting and of the voltage being developedin the subsidiary secondary 28. If the subsidiary secondary isdelivering 150 volts and the variable resistance 32 is set at 3,000 ohmsone third of this voltage or fifty volts would be developed across thevariable resistance, and thus this voltage would be developed across thelamp at such resistance setting. The indicator arrangement is such thata setting of 3,000 ohms in the variable resistance 32 would cause thepointer to lie in the range labeled Good on the face plate, a portion ofwhich is shown in Figure 2. On the other hand, if a partial short on thefence caused a reduction in the fence to ground voltage upon eachenergization, this would be reflected in the subsidiary secondary. If itbe assumed that the voltage was cut in half, the subsidiary secondarywould only develop '75 volts across it and the variable resistance 32would have to exceed about 12,000 ohms in order to cause the lamp 33 tolight. This would cause the indicator to be way over to the left end ofthe scale, in the weak to 7 fair range, almost in the position shown inFigan indicating voltage bearing a predetermined wire 23. This wire isconnected through a fixed resistance 30, a wire 3i, and the variableresistance 32 to the wire 26, so that the fixed and variable resistancesare connected in series to be ure 2.

I It will thus be seen that an indication of the true fence to groundvoltage, and thus the effectiveness of the fence, can be determined atany time by turning the indicator l I slowly until a change in state ofthe light occurs. That is, if the indicator is started at the left orweak side and turned to the right, the light would stay on until acertain position was reached and then would not light. since there wouldnot be sumcient voltage developed across the variable resistance 32 toequal the break-down voltage of the glow lamp 33. The pointer would thenshow whether the condition of the fence was weak, fair, good, or thelike. The process could, of course, be reversed, and the indicatorstarted from the righthand end of its swing and turned slowly until thelight just lit, the results being the same in either case.

While I have described certain embodiments of my invention, it is to beunderstood that it is capable of many modifications. Changes, therefore,in the construction and arrangement may be made without departing fromthe spirit and pended claims.

. adapted to be energized by scope of the invention as disclosed in theap- I claim:

1. Means for indicating the effectiveness of an electric fencecomprising a bare fence wire connected to energizing means adapted toprovide a predetermined open-circuit voltage, including: meanselectrically coupled to the energizing means for providing an indicatingvoltage bearing a predetermined ratio to fence; a, glow lamp adapted tobe energized by the indicating voltage; and manually operable means forvarying the voltage applied to the glow lamp, said last mentioned meansincluding indicating means. v

2. Means for indicating the efiectiveness of an electric fence nected tothe secondary of a transformer having its primary suitab provide atleast one predetermined open-circuit voltage to the fence wire,including: means electrically coupled to the transformer for providing.an indicating voltage bearing a predetermined ratio to the voltage onthe fence; a glow lamp the voltage on the 1 V energized and adapted tocuit test voltage at one comprising a bare fence wire con-- theindicating voltage; and manually operable means for varying thepercentage of the indicating voltage applied to the glow lamp, said lastmentioned means including indicating means calibrated in fenceeffectiveness.

3. Means for indicating the efiectiveness of an electric fencecomprising a. bare fence wire connected through voltage varying means tothe secondary of a transformer having its primary suitably energized,the voltage varying means being adapted to provide a predetermined opencirsetting, including: means electrically coupled to the transformer forproviding an indicating voltage bearing a predetermined ratio to thevoltage on the fence; a glow lamp adapted to be energized by theindicating voltage; and manually operable means for varying thepercentage of the indicating voltage applied to the glow lamp, said lastmentioned means including indicating means calibrated in fenceefiectiveness.

CARL PFANS'I'IEI-IL.

